Coalition governments are sold to voters as exercises in compromise and consensus. They are, in practice, elaborate games of chicken played by parties who must decide, every single day, whether the cost of staying exceeds the cost of leaving.
The puzzle is not why coalitions collapse—partners disagree, leaders clash, scandals erupt—but why they collapse when they do. A cabinet can survive years of internal warfare, then shatter over a minor spending bill. The timing is rarely about the proximate cause. It is about the mathematics of defection.
The junior partner's dilemma
Smaller parties in coalitions face a structural trap. They gain ministerial portfolios and policy influence, but voters struggle to credit them for shared achievements. The senior partner—typically the largest party—absorbs the glory when things go well and deflects blame onto juniors when they don't. Over time, the junior partner's poll numbers erode. Its activists grow restless. Its leaders begin calculating whether they might do better in opposition, rebuilding their brand by attacking the very policies they helped enact.
This is why coalition collapses cluster around two moments: early in a government's term, when a junior partner realizes the deal was worse than expected, or late, when elections loom and differentiation becomes urgent. The middle years are the stable zone—too late to claim the deal was bad faith, too early to pivot to campaign mode.
The confidence vote as nuclear option
Parliamentary systems give coalitions a formal kill switch: the motion of no confidence. But the threat is almost always more powerful than the act. A junior party that triggers early elections risks punishment from voters who resent instability. The senior party, meanwhile, can call the bluff by daring its partners to pull the trigger. This produces the characteristic pattern of coalition politics: endless brinkmanship, theatrical walkouts, and last-minute deals that preserve the status quo until the calculus finally tips.
Germany's traffic-light coalition, which governed from 2021 until its collapse, illustrated the pattern precisely. The Free Democrats spent years signaling discontent, threatening departure, and extracting concessions—until the moment when polls suggested they might not clear the electoral threshold at all, at which point departure became rational regardless of policy.
Why some coalitions survive
The exceptions prove the rule. Coalitions endure when external threats make defection unthinkable (wartime unity governments), when partners occupy such different electoral niches that they aren't competing for the same voters, or when institutional rules raise the cost of collapse (constructive votes of no confidence, which require a replacement government before the current one can fall). Switzerland's permanent grand coalition survives because its consociational design removes the competitive logic entirely—parties share power by formula, not negotiation.
Without such structural guardrails, coalitions are inherently unstable equilibria. They persist only as long as every partner believes the alternative is worse.
Our take
Coalition government is often praised as more democratic than majoritarian systems, forcing compromise and representing a broader swath of voters. This is true in theory. In practice, coalitions produce governments that are simultaneously more fragile and less accountable—fragile because any partner can detonate the arrangement, unaccountable because voters cannot easily assign credit or blame. The real lesson of coalition politics is that stability is not a function of goodwill or shared values. It is a function of incentives. When the math changes, the government falls.
